According to all the test reports my (fill in the blank) lens is not sharp in the corners.

Hmm. I'm a portrait photographer.  Do I really need ultra-sharp corners?

I love manufactured conundrums.  How could I not? I was in the ad business for years before becoming a full time photographer.  We thrived on finding the "pain" for consumers and then giving them a "solution".  "The Malls are too crowded?  We've got acres of free parking!!!"

I was thinking about this after I caught myself mindlessly reading a lens review of the Sony Nex 18-55mm lens on SLRgear.com. They have a nifty-charty thing that shows the performance of the lens you might be considering. It uses colors to show you how sharp a lens is at different apertures and different focal lengths and in different areas of the frame. But here's the issue for me:  I think that the only lenses that test really well on flat charts are macro lenses meant to do well when photographing flat charts because they are made to photograph flat charts.  The rest of the lenses that I'm interested in don't really need to do that, do they?

But the test sites need us to be fearful about picking lenses so they can get eyeballs.  The information can be useful but only if you apply it to your ways of working...

When I looked at the performance of the kit lens for the Nex system I at first was excited to see that, even wide open, it was very sharp and performed very well in the center of the lens.  The air was let out of my balloon when I read on and did all the interactive stuff with the cool graphic sliders. Seems the lens is not as sharp on the corners.  In fact, you've got to stop it down to f8 to get really good corner performance.  Most reviewers tell me that the kit lens won't come close to providing enough performance (across the full frame of the sensor) to work well with the 24 megapixel sensor in the Nex7.  And then there's all the fringing I might find when I do high contrast photographs of little, naked tree branches against the stark sky.  Oh my.

I let my sometimes rational brain take all the information and put it into my mental processing blender and it came out giving the lens a big C+. A snob like me would never consider shooting with it.  Never mind that I actually love lenses that have a high core of sharpness wide open and then gracefully devolve on the edges and corners.  And that includes most of the portrait lenses I have used to best effect, as well as nearly every 50mm lens on the market.

Oh the damage we do to ourselves when we have too much information and not enough theoretical depth to process the information optimally for our own individual needs.

All lenses have curvature of field.  Some are corrected for this and they make really good optics for people who need to photograph stuff that has straight lines.  These might be architectural photographers, still life photographers or technical photographers.  The overwhelming majority of the lenses we buy are used to document life around us.  And the majority of the lenses I buy are pressed into the service of photographing people.  We generally don't need stringent edge to edge sharpness and total lack of optical faults when we use lenses wide open.  We need optics that are crispy enough to do the job.

Many years ago Leica made lenses that the best photographers in the world absolutely swore by.  They still do. But strangely enough, when the lenses from Leica were tested in conventional, flat target ways, they never seemed to put up numbers that matched what we saw on film (or now on our monitors).  Then I read a white paper on optimum design for lenses based on their intended use and I got it. To make a fast, high aperture lens you need to make some compromises.  To make a zoom that's consistent across the zoom range you've got to make some different  compromises and if you want a flat field lens that does good single planes of focus and even illumination you've got to make still other compromises.  The trick is to test the different kinds of lenses and find the ones that work for your style of shooting.  There a few perfect lenses that I can actually afford.  The designers can correct for a lot but would you be willing to pay $10,000 for a 10 pound f4 prime lens to hang on the front of your tiny camera?

And you have to know what compromises are involved.  For example, the 85mm Zeiss 1.4 lens is a super duper optic but in order to make it fast and sharp Zeiss sacrificed corner sharpness wide open and also the design of the lens means that you'll get appreciable focus shift as you stop down from f1.4 to f4.0.  Especially at closer (portrait) distances.  The work arounds are to only focus and shoot at f4 and smaller or to do all of your fine focusing for close up work with a magnified live view image and with the lens stopped down to the actual shooting aperture.  And Zeiss and Lloyd Chambers will tell you that.  You can't have it every which way.

So what am I getting at?  Only that the two lenses I bought for the Sony Nex 7, the 18-55 and the 50mm 1.8 are both more than sharp enough to make wonderful portraits in my style.  Even when used wide open.  The "nifty 50" that everyone loves for the Canon has pretty atrocious performance on the test charts as do most of the 50mm 1.4 lenses from the major makers.  The thing that makes them popular though is the sharp center core and the ability to use them at faster apertures than most zoom-only users ever dream of.  You can't have everything in a lens.  That's why I have separate Macro lenses for those special moments when I find myself longing to shoot test charts.

Measurements are great but interpreting correctly is the part that counts.

Yes, I've gone crazy with the Lightroom presets today.  I'm sure I'll recover.

I think I'm getting the hang of this Sony Nex-7 stuff. Need more practice.

My friend, Noellia the actor, just wrapped up a six month project for Disney and came home to Austin to visit friends and family. She called me up to see if we could get together and spend a little time shooting some photos.  I first met Noellia when I cast her for an ad campaign nearly nine years ago.  She had just turned eighteen and answered a casting call.  We've done many projects together since then and she was a consistent and wonderfully patient model for me during the production of four of my five books on photography.

I thought our "around the town" photo session would be the perfect chance to try out the the little Sony Nex7 and see of what it was capable.  My first intention was to shoot a bunch of images with the bigger a77 camera and to kind of toss the Nex7 into the mix from time to time. But I started out with the 50mm 1.8 lens on the front of the Nex7 and, after a few minutes going back and forth between the two cameras I tossed the a77 into my camera bag and leaned on the little camera for the rest of the day.  Nearly all of the images in this particular blog were shot wide open at f 1.8. I thought the lens performed very well when used wide open.  I also like the focal length and, when used at the right distance from my subject, it was good at throwing backgrounds out of focus. 

I'd read so many articles and reviews that mention two "faults" in this camera.  The first one being battery life that's limited to about 350 to 400 exposures.  I was careful to bring two fully charged batteries along with me but surprised to find that I shot nearly 1,000 frames and still had over 50% power remaining on my first battery at the end. (I don't post-chimp much and never use the built in flash...) The second fault was said to be the rather logically opaque and chaotic menu interface and dial set-up.  It didn't seem very daunting to me.  If you shoot in aperture priority your left control dial takes care of selecting apertures while the right side dial gives you immediate exposure compensation control.  Easy as pie.  Once you figure out that a couple touches on the navigation button gets you to the white balance menu you're pretty much done messing with stuff. I don't change ISO frequently and I tend to find modes I like and to stay with them.  

We started our photo spree at the Barton Springs spillway and then walked down to the bridge that brings Barton Springs road over the miniature train bridge and pedestrian bridge on the east side of Zilker Park.  (The image above was shot under the bridge).  The day was steamy and hot but we didn't pay much attention to the heat.  We were busy having fun photographing and catching up.  Noellia, being the consumate NYC professional actor brought her own make-up and hair pro along with her...

After playing around in the park we headed downtown to make some fun images in the open shade of the buildings on the south side of Second Street.  Of course we ended up at Caffe Medici where we shot with abandon.  (The owner, Michael, is very photo friendly).

I had heard from misguided reviews on the web that the Jpegs out of this camera were mediocre compared to other cameras so, of course, I chose to shoot everything as a large, fine Jpeg.  In fact, I thought the jpegs were highly detailed and well mannered.  At a certain point I tossed everything but the Nex 7 and the 50mm 1.8 back in the bag and stuck the bag in the car.  Intellectually I like the idea of having other lens options.  Aesthetically, I like the black finished 18-55mm lens because it matches the body so well, but the reality is that the 50mm, on that cropped sensor is a pretty compelling match for the way I like to see stuff so I don't see it coming off the front of the camera any time soon.

The only thing I had problems with out in the field was setting the DRO (dynamic range optimizer).  I could get to it in the menu I just couldn't figure out how to change it.  Every thing else seemed pretty straightforward to me.

Noellia and I had a fun afternoon.  She got to see Ben.  Ben got to see her.  She reminded me of why I like to shoot professional actors.... it's the talent.  Tomorrow I'll go out and shoot more stuff with the new camera.  Me liking the Sony Nex 7 camera right now doesn't mean I think all other cameras are bad.  I just think this one is really good.